SIR David Walker – the City grandee who oversaw a review into bank governance for Gordon Brown – is expected to be unveiled today as the new chairman of Barclays.

Sir David, a former deputy governor of the Bank of England, will take over from Marcus Agius in the autumn but will join the beleaguered bank within weeks.

Agius announced his intention to resign after the Libor-rigging scandal that left Barclays’ reputation in tatters.

Sir David, 72, who was chairman of Morgan Stanley International, will be tasked with steering the bank through the most turbulent period in its history and appointing a new chief executive after the rate-fixing affair also claimed the scalp of Bob Diamond.

Sir David, who will receive £750,000 a year, said his “immediate priority” was to find a new chief executive.

Barclays were fined £290million by UK and US regulators for manipulating Libor, the London Interbank Offered lending Rate that affects mortgages and loans.

The affair set off a fierce debate in Westminster over banking ethics and a criminal investigation was launched by the Serious Fraud Office.

At least 15 other institutions, including Royal Bank of Scotland, are being investigated for Libor manipulation.